Robot blade for handling of semiconductor waffers

ABSTRACT

According to one embodiment of the invention, a system for handling semiconductor wafers includes a chamber, a robot associated with the chamber, and a robot blade generally horizontally disposed within the chamber and coupled to the robot at a first end. The robot blade includes a second end distal the first end, in which the second end has a plan view profile that forms a continuously curved surface.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to semiconductor waferprocessing and, more particularly, to a robot blade for handling ofsemiconductor wafers.

BACKGROUND OF THE INVENTION

Semiconductor wafers are subjected to many different processes in orderto manufacture semiconductor die on the wafer. Semiconductor wafers aretypically transferred between processing chambers in order to carry outthe different processes. For efficiency purposes, a robot is used totransfer the wafers between chambers. A robot blade associated with therobot, sometimes referred to as an end effector, is used to transferindividual wafers. Depending on the process chamber that the robot bladeis transferring the semiconductor wafer to, the robot blade may seetemperature fluctuations.

Current robot blades have distal ends (the ends that are proximate thesemiconductor wafers during transferring) that have straight edges thatresult in sharp corners (approximately 90 degrees). Over a period oftime these sharp corners deteriorate by peeling, chipping, delaminating,or other type of deterioration. The deterioration causes particles fromthe robot blade material to imbed in or attach to the semiconductorwafer that it is transferring, which causes all or a portion of thewafer to be defective. Thus, yield is severely degraded, which wastesconsiderable time and money.

SUMMARY OF THE INVENTION

According to one embodiment of the invention, a system for handlingsemiconductor wafers includes a chamber, a robot associated with thechamber, and a robot blade generally horizontally disposed within thechamber and coupled to the robot at a first end. The robot bladeincludes a second end distal the first end, in which the second end hasa plan view profile that forms a continuously curved surface.

Embodiments of the invention provide a number of technical advantages.Embodiments of the invention may include all, some, or none of theseadvantages. In one embodiment, a robot blade utilized for transferringsemiconductor wafers in a transfer chamber includes rounded edges at itsdistal end that eliminates deterioration of any portion of the distalend due to thermal cycling or other factors. This assures that noparticles associated with the robot blade material get embedded in thesemiconductor wafer that the robot blade is handling or fall onto alower semiconductor wafer, which may cause defective wafers. Inaddition, wafer breakage may be avoided by preventing any delaminationor peeling of the distal end of the robot blade. Reducing defects in, orbreakage of, semiconductor wafers during their handling greatly improvesyield, which saves considerable time and money.

Other technical advantages are readily apparent to one skilled in theart from the following figures, descriptions, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and itsadvantages, reference is now made to the following descriptions, takenin conjunction with the accompanying drawings, in which:

FIG. 1 is a partial plan view of a wafer processing system in accordancewith one embodiment of the present invention;

FIG. 2A is a partial plan view of a conventional robot blade;

FIG. 2B is a partial plan view of a robot blade in accordance with oneembodiment of the present invention; and

FIG. 2C is a partial plan view of a robot blade in accordance with oneembodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

Example embodiments of the present invention and their advantages arebest understood by referring now to FIGS. 1 and 2C of the drawings, inwhich like numerals refer to like parts.

FIG. 1 is a partial plan view of a wafer processing system 100 inaccordance with one embodiment of the present invention. Processingsystem 100 generally represents the SEQUEL family of processing systemsmanufactured by Novellus Systems, Inc.; however, other suitableprocessing systems are contemplated by the present invention. In theillustrated embodiment, processing system 100 includes a transferchamber 102 disposed between a pair of load locks 104 a, 104 b and apair of process chambers 106 a, 106 b. Processing system 100 alsoincludes a cool station 108.

Transfer chamber 102 includes a pair of robot blades 200 (also known asend effectors) that function to transfer semiconductor wafers 110 orother suitable substrates within processing system 100. Accordingly,robot blades 200 are able to rotate within transfer chamber 102, asdenoted by double-headed arrow 114, and are able to translate in andout, as denoted by double-headed arrow 116. Any suitable system thatallows robot blades 200 to rotate and translate is contemplated by thepresent invention. In the illustrated embodiment, a robot 130 associatedwith processing system 100 is utilized. Details of various embodimentsof robot blade 200 are described below in conjunction with FIGS. 2B and2C.

Load locks 104 a, 104 b function to house a plurality of one or moresemiconductor wafers 110, which are typically disposed within a boat112. Individual semiconductor wafers 110 sit in boat 112 and wait to bepicked up and transferred by a particular robot blade 200. Asillustrated in FIG. 1, a particular semiconductor wafer 110 has alreadybeen transferred to process chamber 106 a.

Process chambers 106 a, 106 b, function to process semiconductor wafers110. Any suitable processing, such as vapor deposition, may be carriedout in process chambers 106 a, 106 b. In the illustrated embodiment,process chamber 106 a includes a heating block 120 and a plurality ofceramic forks 122. Heating block 120 functions to heat semiconductorwafers 110 to an elevated temperature for processing and ceramic forks120 function to allow robot blades 200 to deliver and removesemiconductor wafers 110 from heating block 120. Typically, heatingblock 120 is at a temperature in the range of approximately 350 to 400°C.; however, the temperature of heating block 120 may be any suitabletemperature depending on the recipe or process.

Because of the nature of semiconductor processing, it is desirable forsemiconductor wafer processors to avoid defects within semiconductorwafers 110. Even the most minute of foreign material or other defectwith respect to semiconductor wafers 110 may ruin all or a portion of aparticular semiconductor wafer 100. Reducing defects in or breakage ofsemiconductor wafers 100 during their handling and/or processing greatlyimproves yield, which saves considerable time and money.

Before the invention described herein, many defective particles werediscovered in semiconductor wafers in a processing system similar toprocessing system 100 of FIG. 1. One reason for these defectiveparticles was the shape of the robot blade being used in those priorsystems. Such a robot blade is shown and described in conjunction withFIG. 2A.

FIG. 2A is a partial plan view of a conventional robot blade 250. Adistal end 251 of robot blade 250 is defined by a pair of chamfers 252at the outer corners thereof, a pair of straight edges 253, and a notch254 generally positioned in the center of robot blade 250. Straightedges 253 and notch 254 define a pair of corners 256. Corners 256 are attypically at ninety degree angles; however, corners 256 may also be atforty-five degree angles. It is these corners 256 that have providedproblems with robot blade 250 in that deterioration occurs at corners256 due to the temperature cycling that robot blade 250 encounters fromthe transfer of semiconductor wafers 110 to and from heater block 120.Deterioration of corners 256, such as peeling, chipping, delaminationand other types of material degradation result in small particles beingimbedded in or attaching to all or a portion of semiconductor wafers110, which causes defects in the wafers. Depending on the type ofdefect, it may also cause breakage of semiconductor wafer 100.Typically, the size of the particles that have been found to causedefective semiconductor wafers 110 are between 0.5 to ten microns andthe composition of such particles range anywhere from molybdenum,cobalt, iron, chromium, nickel, magnesium, silicon, and other suitableparticles. The type of particles depends upon the type of material thatrobot blade 250 is formed from.

One reason for the deterioration of corners 256 is that there is lessheat sink proximate corners 256. Therefore, according to the teachingsof one embodiment of the present invention, new robot blades have beendesigned that increase the heat sinks at the distal ends of the robotblades to eliminate deterioration of any portion of the distal ends ofthe robot blades. This substantially reduces or eliminates the risk ofhaving defective particles associated with the semiconductor wafers,which greatly improves yield. Various embodiments of the new robotblades are illustrated below in conjunction with FIGS. 2B and 2C.

FIG. 2B is a partial plan view of a robot blade 200 a in accordance withone embodiment of the present invention. Robot blade 200 a may be formedfrom any suitable material; however, in a particular embodiment, robotblade 200 a is formed from molybdenum. Although not illustrated in FIG.2B, robot blade 200 a may have any suitable thickness. In addition, withreference to FIG. 1, robot blade 200 a is integrally formed from onepiece of material. In other words, robot blade 200 a is a one-piecerobot blade, devoid of any gaskets or other parts, that couples to anysuitable robot within transfer chamber 102.

Robot blade 200 a has a distal end 202 that avoids the problemsassociated with prior robot blades, such as robot blade 250 as describedin FIG. 2A. In the illustrated embodiment, distal end 202 has a planview profile (i.e., a profile as viewed from the top) that forms acontinuously curved surface 204 extending between a first side 205 and asecond side 206 of robot blade 200 a. First side 205 and second side 206are straight-edged sides of robot blade 200 a that are substantiallyparallel to one another. Continuously curved surface 204 may be convexor concave with respect to first side 205 and second side 206 and mayhave any suitable curved shape, such as circular, elliptical,semi-elliptical, parabolic, hyperbolic, arcuate, catenary, or othersuitable curvilinear shape. Continuously curved surface 204 is devoid ofany sharp corners as in prior robot blades that would causedeterioration of distal end 202.

FIG. 2C is a partial plan view of a robot blade 200 b in accordance withanother embodiment of the present invention. Similar to robot blade 200a, robot blade 200 b may be formed from any suitable material and haveany suitable thickness. One difference between robot blade 200 a androbot blade 200 b is that robot blade 200 b has an alignment notch 208formed in a distal end 210. Alignment notch 208, which may also act as ascanning gap, may have any suitable size and any suitable shape. In oneembodiment, a plan view profile of notch 208 forms a suitably curvedsurface, such as circular, elliptical, semi-elliptical, parabolic,hyperbolic, arcuate, catenary, or other suitable curvilinear shape As aresult of notch 208, a pair of protrusions 212 exist at distal end 210.Protrusions 212 may also have any suitable size and shape; however, itis preferred that a plan view profile of protrusions 212 be formed froma continuously curved surface, such as circular, elliptical,semi-elliptical, parabolic, hyperbolic, arcuate, catenary, or othersuitable curvilinear shape. In a particular embodiment of the presentinvention, the plan view profile of distal end 210 of robot blade 200 b,which is defined by the plan view profiles of protrusions 212 andalignment notch 208 form a generally sinusoidal shape.

In one embodiment of the invention, robot blade 200 a and robot blade200 b are designed for transferring semiconductor wafers 100 between anambient temperature environment and an elevated temperature environment.For example, referring to FIG. 1, processing system 100 may be asuitable chemical vapor deposition processing system in whichsemiconductor wafers 110 are transferred from boat 112, which is atapproximately ambient temperature, to processing chamber 106 a havingheating block 120, which is at an elevated temperature, such asapproximately 400° C. In other embodiments, robot blades 200 a, 200 bare designed for other suitable processing systems. In addition, in oneembodiment of the invention, both robot blades 200 a and 200 b aredevoid of any vacuum ports.

Although embodiments of the invention and their advantages are describedin detail, a person skilled in the art could make various alterations,additions, and omissions without departing from the spirit and scope ofthe present invention as defined by the appended claims.

1. A system for handling semiconductor wafers, comprising: a chamber; arobot associated with the chamber; and a robot blade generallyhorizontally disposed within the chamber and coupled to the robot at afirst end, the robot blade comprising a second end distal the first end,the second end having a plan view profile that forms a continuouslycurved concave surface.
 2. The system of claim 1, wherein the second endextends from a first side to a second side of the robot blade, the firstand second sides substantially parallel.
 3. (cancelled)
 4. The system ofclaim 1, further comprising a notch formed in the distal end, the notchalso having a plan view profile that forms a continuously curvedsurface.
 5. The system of claim 1, wherein the robot blade is integrallyformed from one piece of material.
 6. The system of claim 1, wherein thecontinuously curved surface is formed from one or more curved shapesselected from the group consisting of circular, elliptical,semi-elliptical, parabolic, hyperbolic, arcuate, and catenary.
 7. Thesystem of claim 1, further comprising a load lock at a first temperatureapproximately equal to ambient temperature and a processing chamberhaving a heating block at an elevated temperature, wherein the robot isoperable to direct the robot blade to transfer semiconductor wafers fromthe load lock to the heating block.
 8. The system of claim 7, whereinthe elevated temperature is between approximately 350° C. andapproximately 400° C.
 9. A system for handling semiconductor wafers,comprising: a chamber; a robot associated with the chamber; and a robotblade generally horizontally disposed within the chamber and coupled tothe robot at a first end, the robot blade comprising a second end distalthe first end, and first and second generally parallel sides, the secondend extending from the first side to the second side and comprising: anotch having a generally concave surface with respect to the first andsecond sides; a pair of protrusions each having a generally concavesurface with respect to the first and second sides; and wherein a planview profile of the notch and pair of protrusions form a continuouslycurved surface from the first side to the second side.
 10. The system ofclaim 9, wherein the concave surface of the notch is formed from one ormore curved shapes selected from the group consisting of circular,elliptical, semi-elliptical, parabolic, hyperbolic, arcuate, andcatenary.
 11. The system of claim 9, wherein the concave surfaces of thepair of protrusions are formed from one or more curved shapes selectedfrom the group consisting of circular, elliptical, semi-elliptical,parabolic, hyperbolic, arcuate, and catenary.
 12. The system of claim 9,wherein the robot blade is integrally formed from one piece of material.13. The system of claim 9, wherein the robot blade is devoid of anyvacuum ports.
 14. The system of claim 9, further comprising a load lockat a first temperature approximately equal to ambient temperature and aprocessing chamber having a heating block at an elevated temperature,wherein the robot is operable to direct the robot blade to transfersemiconductor wafers from the load lock to the heating block.
 15. Thesystem of claim 14, wherein the elevated temperature is betweenapproximately 350° C. and approximately 400° C.
 16. (cancelled): 17.(cancelled):
 18. (cancelled):
 19. (cancelled):
 20. (cancelled):